KR100722930B1 - Apparatus and method for playing audio using dma - Google Patents

Abstract

An apparatus for mixing and reproducing a plurality of audio data, the apparatus comprising: a memory for storing the plurality of audio data; An audio processor for editing and processing the plurality of audio data; A DMA controller for receiving a control signal for reading or writing data from the audio processor, muxing a plurality of data from the memory, and outputting the muxed data; And an input / output interface for transmitting the edited data to a digital-to-analog converter (DAC). According to the present invention, it is possible to reproduce a plurality of audio data without adding additional hardware and increasing the load of the audio processor.

Audio, DMA, DMA, Audio Processor, PCM, Mixed, Mux

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an apparatus,

1 is a block diagram showing a general audio mixing / reproducing apparatus;

2 is a block diagram showing an audio mixing / reproducing apparatus according to the prior art;

3 is a block diagram showing an audio mixing / reproducing apparatus according to the prior art;

FIG. 4 illustrates a data process of an audio MUX according to FIG. 3; FIG.

5 is a block diagram showing an audio mixing / reproducing apparatus according to a preferred embodiment of the present invention.

6 is a block diagram of a DMA controller in accordance with a preferred embodiment of the present invention.

FIG. 7 illustrates an audio mixing / reproducing process according to a preferred embodiment of the present invention. FIG.

8 is a diagram illustrating a data processing process of a general audio DMA;

The present invention relates to an audio mixing / reproducing apparatus and method using DME. More specifically, the present invention relates to an audio mixing / reproducing apparatus and method using DME which can increase efficiency of data processing by feeding a plurality of digital audio data by DME And methods.

In recent years, an audio reproducing apparatus has been used as a terminal for processing digital data. In recent years, an audio reproducing apparatus has been proposed as a terminal for processing audio data, And a process of converting an audio signal into digital data in order to increase transmission efficiency through a network are generally performed, and a process of compressing and expanding digital data is generally performed.

1 is a block diagram showing a general audio mixing and reproducing apparatus. Referring to FIG. 1, an audio reproducing apparatus includes an audio processor 100, a memory 106, a DAC 108, and an audio output apparatus 110 .

Generally, the analog audio signal is converted into digital data by an ADC (not shown) and stored in the memory 106, which is converted, through sampling, quantization, and encoding, to digital data.

Sampling (sampling) is a process of extracting a sample with respect to an analog waveform at a predefined sampling frequency, quantization is a process of expressing a data value of the extracted sample by a predetermined number of bits, and the quantized data is encoded It is expressed as digital information.

The audio processor 100 edits and processes audio data and may be a digital signal processor (DSP) provided separately from a central processing unit (CPU).

If audio output is required, the audio processor 100 reads the PCM data stored in the memory 106 and transmits the PCM data stored in the memory 106 to the DAC 110 via the I2S interface 104. [ The DAC 108 converts the PCM data, which is digital data, into an analog signal and outputs the analog signal to the outside via an audio output device (speaker) 110.

1, a direct memory access (DMA) controller 102 controls to transfer data directly between a peripheral device such as the DAC 108 and the audio output device 110 and the memory 106 without going through an audio processor .

The DMA controller 102 is dedicated to the process of reading data from or writing data to the memory on behalf of the processor.

In the audio reproducing apparatus, there may be a case where various sound sources are stored in the memory and various sound sources are simultaneously reproduced. For example, when there is a call connection request from the outside during playback of MP3 data on the mobile, It is often necessary to selectively reproduce various sound sources such as an output sound.

2 is a block diagram showing an audio mixing / reproducing apparatus according to the prior art.

FIG. 2 shows a configuration required for mixing and reproducing a plurality of audio data in hardware. FIG. 2 shows a configuration in which a DAC 210 muxes and outputs a plurality of audio data.

As shown in FIG. 2, in the DAC 210, two input / output ports must be provided in the DAC 210, and since a plurality of audio data must be received from the audio processor 200, The I2S interfaces 206 and 208 are required.

Therefore, the audio reproducing apparatus shown in FIG. 2 has a problem that an area is increased because the DAC 210 has many input / output ports, and the manufacturing process is troublesome due to the necessity of an additional I2S interface, .

FIG. 3 is a block diagram illustrating an audio mixing / reproducing apparatus according to the related art. In FIG. 3, a configuration for mixing and reproducing a plurality of audio data in software is shown without additional hardware.

A program for feeding a plurality of audio data is ported to the audio processor 300 shown in FIG. 3. For example, the audio processor 300 reads two pieces of PCM data (PCM Data 1 and PCM Data 2) from the memory 306, (Mixed PCM Data) is stored in the memory 306 again.

FIG. 4 illustrates a data processing process of the audio MUX according to FIG. 3. Referring to FIG. 4, a conventional audio MUX performs a process of muxing a plurality of audio data from a memory, And stores it in the memory again.

The meaning code of the conventional audio MUX is as follows.

for (loop = 1; loop <= Sample_Count; loop ++)

{

pcm1 = read_one_sample_of_sound1_from_memory (loop);

pcm2 = read_one_sample_of_sound2_from_memory (loop);

pcm = mux_one_sample (pcm1, pcm2);

write one_sample_of_output_sound (pcm);

}

As can be seen from the meaning code of the above-mentioned audio MUX, when the audio mux is processed by software, the audio MUX includes a process of reading a plurality of data from a memory, a process of muxing a plurality of data, And the process of writing the muxed data back to the memory is performed.

3, the DMA controller 302 reads data stored in the memory 306 in this manner and outputs the data to the DAC 310 via the I2S interface 308. The DAC 310 reads the mixed data To analog data.

The audio reproducing apparatus shown in FIG. 3 and FIG. 4 does not require any additional hardware, so that a dual port DAC and an additional I2S interface are not required. However, in the audio processor, There is a problem that the load of the audio processor is increased because the data must be stored in the memory again and the cost of the audio processor is required to be higher than a certain level in order to perform the process, .

In order to solve the problems of the related art as described above, the present invention proposes an audio mixing / reproducing apparatus and method using a DM which can reproduce a plurality of audio data without adding any additional hardware.

It is another object of the present invention to provide an audio mixing / reproducing apparatus and method using a DM which does not increase the load of an audio processor in reproducing a plurality of audio data.

In order to achieve the above object, according to a preferred embodiment of the present invention, there is provided an apparatus for mixing and reproducing a plurality of audio data, the apparatus comprising: a memory for storing the plurality of audio data; An audio processor for editing and processing the plurality of audio data; A DMA controller for receiving a control signal for reading or writing data from the audio processor, muxing a plurality of data from the memory, and outputting the muxed data; And an input / output interface for transmitting the edited data to a digital-to-analog converter (DAC).

The DMA controller comprising: a data buffer for temporarily storing a plurality of audio data read from the memory and the muxed data; And a mux for muxing a plurality of audio data temporarily stored in the data buffer.

Here, it is preferable that the mux muxes the plurality of audio data according to a predetermined weight, and the input / output interface is preferably an I2S interface.

According to another aspect of the present invention, there is provided a data processing apparatus including: a memory for storing a plurality of audio data; an audio processor for editing and processing the plurality of audio data; a DMA controller for performing data reading or writing; A method performed in the DMA controller, the method comprising: (a) receiving a control signal for reading or writing the plurality of audio data from the audio processor, in an apparatus including an input / output interface for outputting to a digital / analog converter; (B) feeding the plurality of audio data in response to the control signal; And (c) transmitting the edited data to the input / output interface.

Wherein the step (b) comprises: reading a plurality of audio data from the memory and temporarily storing the audio data in a data buffer; Midding data temporarily stored in the data buffer; And temporarily storing the muxed data in the data buffer.

The muxing step may include muxing the plurality of audio data according to preset weights.

Hereinafter, preferred embodiments of an audio mixing / reproducing apparatus and method using a DME according to the present invention will be described in detail with reference to the accompanying drawings.

5 is a block diagram illustrating an audio mixing / reproducing apparatus according to an exemplary embodiment of the present invention.

5, an audio mixing / reproducing apparatus according to the present invention includes an audio processor 500, a DMA controller 502 performing a muxing function, a memory 506, an I2S interface 508, a DAC : 510 and an audio output device 512. [

A DMA controller 502 according to the present invention is additionally provided with a module 504 for feeding a plurality of pieces of audio data (PCM data), and such a DMA controller 502 receives a plurality of audio data ), Performs a process of feeding the data, and transmits the fed data to the DAC 510 as one output.

Here, the memory 506 stores a plurality of audio data, and may include a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory, and an SD memory card.

In the related art, a plurality of audio data is dubbed in the DAC, and a hardware configuration is additionally required. In addition, a load of the audio processor is increased as a result of performing a middling process in software in the audio processor. However, according to the present invention, As the DMA controller 502 performing the data input / output function feeds a plurality of pieces of audio data (PCM data), it is possible to solve the problem of adding a separate hardware component or increasing the load of the audio processor.

6, a DMA controller according to an embodiment of the present invention includes a controller 600, a data buffer 602, an address register 604, A word count register 606, a control register 608, and a MUX 610. [

The control unit 600 controls the entire read and write operations of the DMA controller 502 and receives a predetermined control signal from the audio processor 500 so that a process of reading or writing data can be performed.

The data buffer 602 temporarily stores the data read from the memory 506 or temporarily stores the muxed data according to the present invention before outputting the data to the DAC 510. [

The address register 604 records an address for transmitting data to a memory or a peripheral device (for example, a DAC). When data is transferred, the register value is incremented by one.

On the other hand, the word count register 606 is a register for indicating the size of data to be transmitted. When the data is transferred, the word processor 606 transmits the word number information of the data to be transmitted by the audio processor 500 to the DMA controller 502, The count register 606 decrements the register value by 1 each time one word of data is transferred and decrements the register value until the value becomes 0 (until the data transfer is completed).

The control register 608 is used to specify a transfer mode such as data read and write.

According to a preferred embodiment of the present invention, when there are a plurality of audio data in the data buffer 602, the mux 610 performs a process of muxing a plurality of audio data.

On the other hand, in a mixed reproduction of a plurality of audio data, there may be a predetermined weight for each audio data. For example, if it is necessary to reproduce a ringing tone by a call request during MP3 playback on a mobile, A weight of 0 for MP3, and a weight of 1 for the ringtone.

The DMA controller 502 according to the present invention directly transmits the muxed data to the DAC 510. The DMA controller 502 according to an embodiment of the present invention performs a muxing process using a predetermined weight information for a plurality of audio data, .

For convenience of understanding the mixed reproduction of audio data according to the present invention, a data processing process of a general audio DMA and a process of a DMA controller according to the present invention will be compared.

8 is a diagram illustrating a data processing process of a general audio DMA controller.

Referring to FIG. 8, a general audio DMA controller reads a plurality of audio data from a memory and sends the audio data to an output terminal.

The meaning code of a general DMA controller is as follows.

for (loop = 1; loop <= Sample_Count, loop ++)

{

pcm = read_one_sample_from_memory (loop);

send_one_sample_to_I2S_output_block (pcm);

}

As described in the above code, the general DMA controller in the audio mixing / reproducing apparatus performs a process of reading data from the memory and transmitting it to the DAC through the I2S interface.

However, according to the present invention, the DMA controller 502 performs a process of outputting the muxing process and the muxed data directly to the I2S interface.

7, a DMA controller according to an embodiment of the present invention reads a plurality of audio data from a memory and mutes it, as shown in FIG. 7. Referring to FIG. 7, , And outputs it directly to the I2S interface.

The meaning code of the DMA controller 502 according to the present invention is as follows.

for (loop = 1; loop <= Sample_Count; loop ++)

{

pcm1 = read_one_sample_of_sound1_from_memory (loop);

pcm2 = read_one_sample_of_sound2_from_memory (loop);

pcm = mux_one_sample (pcm1, pcm2);

send one_sample_of_output_sound (pcm);

}

The DMA controller 502 according to the present invention performs a process of reading a plurality of data from the memory 506 and a process of muxing the read data, And transmits the data to the interface.

According to the present invention, the data mixing process can be performed by referring to preset weight information, and the audio output device 512 can output the sound source according to the weight.

As described above, the DMA controller 502 according to the present invention includes a mux 610 to perform a muxing process of a plurality of audio data in addition to reading / writing of data, and transmits the mux data to the I2S interface. And does not increase the load of the audio processor.

In the above description, the DMA controller and the DAC are connected through the I2S interface. However, this is merely an example, and it should be understood that the application of the I / O interface other than the I2S interface may also be included in the scope of the present invention.

It will be apparent to those skilled in the relevant art that various modifications, additions and substitutions are possible, without departing from the spirit and scope of the invention as defined by the appended claims. The appended claims are to be considered as falling within the scope of the following claims.

As described above, according to the present invention, there is an advantage that it is not necessary to provide a dual-port DAC and an additional I2S interface because the DMA controller carries out the audio data muxing process.

In addition, according to the present invention, since the DMA controller transmits the muxed data directly to the I2S interface after performing the muxing process, there is an advantage that the audio data processing efficiency can be improved without increasing the load of the audio processor.

Claims (7)

An apparatus for mixing and reproducing a plurality of audio data, A memory for storing the plurality of audio data; An audio processor for editing and processing the plurality of audio data; A DMA controller for receiving a control signal for reading or writing data from the audio processor, muxing a plurality of data from the memory, and outputting the muxed data; And And an input / output interface for transmitting the muxed data to a digital-to-analog converter (DAC). The method according to claim 1, The DMA controller comprising: A data buffer for temporarily storing a plurality of audio data read from the memory and the muxed data; And And a mux for muxing a plurality of audio data temporarily stored in the data buffer. 3. The method of claim 2, And the mux muxes the plurality of audio data according to a predetermined weight. The method according to claim 1, Wherein the input / output interface is an I2S interface. An audio processor for editing and processing the plurality of audio data, a DMA controller for reading or writing data, and an input / output interface for outputting the data transmitted by the DMA controller to a digital / analog converter A method performed in the DMA controller, the method comprising: (A) receiving a control signal for reading or writing the plurality of audio data from the audio processor; (B) reading a plurality of data from the memory in response to the control signal; And And (c) transmitting the muxed data to the input / output interface. 6. The method of claim 5, The step (b) Reading a plurality of audio data from the memory and temporarily storing the audio data in a data buffer; Midding data temporarily stored in the data buffer; And And temporarily storing the muxed data in the data buffer. 6. The method of claim 5, Wherein the muxing step muxes the plurality of audio data according to a predetermined weight.

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